This is pretty much unneeded because accepting BTC doesnt mean that your business intended to target only BTC user as some people might be interested to know more about BTC the moment they see a business only accepts it as a payment form. Some people might be enthusiast enough to learn about it but it depends on what is your target customer. If your target is a 50 year old grandpa than I'd assume it will be a bad business but if it is a young teens and such then it could be a good idea.

In fact it may not be harmful to offer BTC only as a payment method but it will not be as successful as accepting both FIAT and BTC as a payment . Accepting both could be much usefull and that wont prevent people from stopping and turn away the moment they saw that it accepts BTC only